The present invention relates to an electrode for electrochemically machining a workpiece. The electrode is a cathodically polarized tool electrode. It has a geometry that corresponds to the geometry to be removed on the workpiece, at least in a machining range, and perviousnesses within the electrode that allows an electrolyte to flow through and exit at the electrode surface, at least in the area of the machining range. The invention further relates to a method for electrochemically machining a workpiece with an electrode and to uses for the electrode according to the invention.
A wide variety of electrodes for electrochemical machining of a workpiece are known in the art. For example, U.S. Pat. No. 4,522,692 discloses an electrode of the aforementioned type. The electrode is constructed of a plurality of elements, namely an electrode body and a porous electrode tip or a porous electrode end. The electrode tip or electrode end is made of a sintered metal powder. A drawback of the known electrodes, however, is that they are not capable of ensuring a uniform electrolyte flow or a uniform and sufficient electrolyte exchange.
Methods for electrochemical machining of a workpiece using an electrode are also known in the art. Electrochemical machining is a method for the exact and highly precise machining of surfaces. With electrochemical machining the surface of the workpiece is usually machined by an electrode, such that an electrochemical reaction of the workpiece and the electrolyte between the workpiece and the electrode causes material to be removed from the workpiece. In typical electrochemical machining processes, the distances between the electrodes and the workpiece range from 1 to 2 mm. To produce finer structures and shapes, this distance may be reduced to the order of 10 to 50 μm and less (precision electrochemical machining). With such precise electrochemical machining, an exchange of the electrolyte can be ensured only through vibration of the electrode and correspondingly high electrolyte pressures in the gap between the electrode and the workpiece. However, this involves the risk, particularly with thin-walled workpieces, that the workpiece will be damaged and, in particular, warped. Furthermore, while the gap is opened by vibration, the flow of current is interrupted to prevent uncontrolled and uneven removal. This reduces the removal rate.
Thus, it is an object of the present invention to provide an electrode of the above-described type, which ensures uniform electrolyte flow and uniform and sufficient electrolyte exchange in an area between the electrode and a workpiece to be machined as well as high removal rates.
It is a further object of the present invention to provide methods for electrochemical machining of a workpiece using an electrode, which ensure a uniform electrolyte flow and uniform and sufficient electrolyte exchange in an area between the electrode and a workpiece to be machined as well as high removal rates.